Catheter-Based Ultrasound Hyperthermia System for 30-Targeted Thermal Therapy Hyperthermia combined with radiotherapy and/or chemotherapy for the treatment of locally advanced or recurrent pelvic tumors (e.g., prostate, cervix) has been shown to dramatically improve clinical response. The deep-regional heating techniques used in many of these studies do not effectively localize a prescribed temperature distribution nor provide a means of verifying delivery of adequate thermal dose. Our overall research plan is to develop highly-controllable interstitial and endocavity ultrasound heating technology to be integrated with HDR brachytherapy as a means to significantly enhance treatment efficacy of combining hyperthermia with standard radiation and chemotherapy for cervical cancer patients with bulky Stage IB-IllB (possibly IVA) disease, recurrent prostate cancer, and other persistent or advanced pelvic tumors. Relying upon our expertise developing catheter-based ultrasound heating technology, including previous clinical treatments of pelvic disease, we plan to expeditiously complete advanced development of interstitial and endocavity hyperthermia applicators and treatment delivery systems (Aim 1). This includes the integration of an ultrasound applicator and temperature sensing within an endocavity HDR ring applicator for heating from directly within the uterine cervix, and a transurethral applicator for heating prostate. Image based treatment planning programs and thermal models will be developed and used to determine treatment strategies and applicator configurations that dramatically improve treatment delivery and heating conformability (Aim 2). Thus, prior to or after the HDR treatment, the same catheters and devices used to deliver radiotherapy can be used to deliver conformable hyperthermia and monitor intratumoral temperatures. A clinical study of this catheter-based ultrasound system will be performed to provide design feedback and determine the feasibility of this approach (Aim 3). The information obtained from this effort will be used to guide future development as necessary and the design/implementation of Phase l/ll studies to determine safety and efficacy of this approach for specific sites. The same technique can be modified and utilized for applying 3D conformal hyperthermia to other sites treated with HDR brachytherapy (e.g., head &neck, melanoma, breast).